1. Field of the Invention
The present invention is directed to an optical symbol reader and, more particularly, to a hand held optical symbol reader that uses a random access memory as a light detecting array and a gradient refractive index material as a lens.
2. Description of the Related Art
The encoding of data on parts and retail merchandise has been widely accepted and standardized in the use of a universal product code symbol. The universal product code symbol utilizes a combination of varying width bars and spaces to optically encode data. The use of a symbol that carries information in only one dimension (width) creates inherent limitations due to space restrictions and optical resolution limits of detecting elements. These limitations combine to restrict the amount of data that can be represented by the symbol and prevent its use on small parts and packages. The reading operation for the standard bar code requires either hand scanning over the bar code by moving the light source and detector element or automatic scanning with relatively expensive hardware in which a laser beam is moved across the bar code symbol. This requirement for movement to scan the bar code symbol unnecessarily complicates the scanning task by the operator as well as the equipment associated with detecting the symbol.